The proposed research is aimed at elucidating various aspects of pituitary hormone (e.g., lutropin, somatotropin, and corticotropin) conformation, metabolism (including plasma clearance, urinary excretion, catabolism, and biotransformations), and mechanism-of-action. Also, research is being conducted on human chorionic gonadotropin. Conformational studies involve measurements of circular dichroism, electron-spin-resonance, and ultracentrifugation. For the gonadotropins particular attention is devoted to a clarification of the conformational changes occurring upon subunit association-dissociation, mechanisms involved in plasma clearance, and mechanism-of-action. For somatotropin, emphasis is on the conformation and activities of various fragments. Detailed metabolic and conformational studies are being conducted on corticotropin. Molecular aspects of hormone-receptor interactions are being investigated using both whole-animal and cell culture systems for the three aforementioned pituitary hormones. Comparative conformational studies are being conducted on several non-pituitary hormones and factors, e.g., (hypothalamic) somatostatin, (submaxillary) epidermal growth factor, and (pancreatic) insulin and glucagon. BIBLIOGRAPHIC REFERENCES: "Evidence for Structural Dissociation of Two Biologic Actions of Growth Hormone," L.A.Holladay, J.H. Levine, W.E. Nicholson, D.N. Orth, W.D. Salmon, Jr., and D. Puett. Biochim. Biophys. Acta 381, 47-60 (1975). "The Metabolism of Luteinizing Hormone. Plasma Clearance, Urinary Excretion, and Tissue Uptake," M. Ascoli, R.A. Liddle, and D. Puett. Molecular Cellular Endocrinology 3, 21-36 (1975).